diff options
| author | Peilin Ye <yepeilin@google.com> | 2025-01-03 02:04:18 +0000 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2025-01-06 15:07:41 +0100 |
| commit | 8c21f88407d230543435445903cfbb4d05b7b339 (patch) | |
| tree | eb6375949e7373db55087a5681686635aeaec573 | |
| parent | 66bb58ac06c229f213ff974aebc453f1ac6dde09 (diff) | |
bpf, arm64: Emit A64_{ADD,SUB}_I when possible in emit_{lse,ll_sc}_atomic()
Currently in emit_{lse,ll_sc}_atomic(), if there is an offset, we add it
to the base address by doing e.g.:
if (off) {
emit_a64_mov_i(1, tmp, off, ctx);
emit(A64_ADD(1, tmp, tmp, dst), ctx);
[...]
As pointed out by Xu, we can use emit_a64_add_i() (added in the previous
patch) instead, which tries to combine the above into a single A64_ADD_I
or A64_SUB_I when possible.
Suggested-by: Xu Kuohai <xukuohai@huaweicloud.com>
Signed-off-by: Peilin Ye <yepeilin@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Xu Kuohai <xukuohai@huawei.com>
Link: https://lore.kernel.org/bpf/9ad3034a62361d91a99af24efa03f48c4c9e13ea.1735868489.git.yepeilin@google.com
| -rw-r--r-- | arch/arm64/net/bpf_jit_comp.c | 12 |
1 files changed, 4 insertions, 8 deletions
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 8ee9528d8795..8446848edddb 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -662,8 +662,7 @@ static int emit_lse_atomic(const struct bpf_insn *insn, struct jit_ctx *ctx) u8 reg = dst; if (off) { - emit_a64_mov_i(1, tmp, off, ctx); - emit(A64_ADD(1, tmp, tmp, dst), ctx); + emit_a64_add_i(1, tmp, reg, tmp, off, ctx); reg = tmp; } if (arena) { @@ -734,7 +733,7 @@ static int emit_ll_sc_atomic(const struct bpf_insn *insn, struct jit_ctx *ctx) const s32 imm = insn->imm; const s16 off = insn->off; const bool isdw = BPF_SIZE(code) == BPF_DW; - u8 reg; + u8 reg = dst; s32 jmp_offset; if (BPF_MODE(code) == BPF_PROBE_ATOMIC) { @@ -743,11 +742,8 @@ static int emit_ll_sc_atomic(const struct bpf_insn *insn, struct jit_ctx *ctx) return -EINVAL; } - if (!off) { - reg = dst; - } else { - emit_a64_mov_i(1, tmp, off, ctx); - emit(A64_ADD(1, tmp, tmp, dst), ctx); + if (off) { + emit_a64_add_i(1, tmp, reg, tmp, off, ctx); reg = tmp; } |